Rapid determination of lenalidomide in rat plasma by an ultra performance liquid chromatography/tandem mass spectrometric method

A new, rapid, and specific ultra performance liquid chromatographic assay with mass spectrometric detection has been developed and validated for the quantitative determination of the antiangiogenic agent lenalidomide in rat plasma using thalidomide as an internal standard with electro spray ionization in multiple-reaction monitoring mode. The analyte and internal standard were extracted by liquid-liquid extraction using methyl-tert-butyl ether solvent. Chromatography was performed isocratically on Acquity BEH C18 column using a mobile phase consisting of a mixture of buffer, acetonitrile, and formic acid in ratios of 30:70:0.1 (v/v/v). The method had a chromatographic run time of 1.2 min. The calibration curve was fit to a linear response concentration data over a range of 0.06-60.00 mu M using a weighting factor of 1/x2. The intra- and inter-day precision and accuracy results were well within the acceptable limits. The validated method was successfully applied for routine analysis of the pharmacokinetics of lenalidomide.